https://www.bancaditalia.it/media/approfondimenti/2019/pop-bari/approfondimenti-popBari.pdf
https://www.bbc.com/news/world-europe-54964858
http://www.sgi-network.org/2017/About
https://www.cer.eu/in-the-press/geopol%C3%ADtica-est%C3%A1-levar-alemanha-tornar-se-mais-pragm%C3%A1tica-na-frente-or%C3%A7amental